GB1286887A - Apparatus for determining corneal contour - Google Patents

Abstract

1286887 Corneal measurement WESLEYJESSEN Inc 12 Oct 1970 48376/70 Heading G2J An apparatus for measuring corneal contour shines rings of light upon the cornea, photographs the reflected image so that the image may be compared with that of a perfect sphere and any deviation used to calculate the contour of the cornea. A housing 82 mounts a fluorescent tube 80, an electronic flash-tube 122, a camera lens 98, a polaroid camera 120 an eye-piece 100 with reflex mirrors 106, 108 and a target structure 10. The structure 10 comprises two shells 38, 40 which are interiorly coated with reflective material except at areas 86, 88, 90, 54, 56, and the frushoconical end (76) of the shell 40. These areas are arranged to direct concentric pans of rings of light on to the cornea as in Fig.10 (not shown). The patients chin is placed upon an adjustable rest 14 and his forhead against a rest 16. The rest 14 is adjusted to centre the rings of light upon the cornea and the device is focused by moving the housing 82 relative to the patient by means of a screwed rod 124 and ball joint 130 which permits the housing to move on a base 12. The reflex mirror 108 has an aperture 107 which permits light from the tube 80 to be reflected via the mirror 106 to a cross wire 99 which enables the patient to focus his eye and also, when reflected back from the cornea, enables split image focusing to be obtained in the eye-piece 100. The shell 38 also has three small apertures 176 which direct spots of light on to the cornea which appear as spots (170), (172), Fig.11 (not shown), which enables the photograph to be oriented with respect to the cornea. Movement of the mirror 106 upon taking the photograph switches off the tube 80 and illuminates the flash-tube 122.